Cuesta Alberto, Cerezuela Rebeca, Esteban M Angeles, Meseguer José
Fish Innate Immune System Group, Department of Cell Biology and Histology, Faculty of Biology, University of Murcia, Murcia, Spain.
J Pineal Res. 2008 Aug;45(1):70-8. doi: 10.1111/j.1600-079X.2008.00557.x. Epub 2008 Feb 17.
Melatonin, a molecule produced in the pineal gland and retina of vertebrates, plays a major role in day-night circadian rhythms and other physiological processes, including the immune responses. Because little is known in this respect in fish, we have evaluated the in vivo role of melatonin in the main innate immune activities and the expression of immune-relevant genes in a teleost fish, the gilthead seabream (Sparus aurata L.). An intraperitoneal injection of 1 or 10 mg melatonin/kg of body weight produced a dose-time dependent increase in circulating melatonin serum levels. Several innate immune responses such as peroxidase, phagocytic, reactive oxygen intermediates and cell-mediated cytotoxic activities were significantly enhanced by the administration of melatonin at different sampling times. The expression of immune-relevant genes such as interleukin-1beta, major histocompatibility complex, virus-related response (interferon-regulatory factor-1 and Mx) and lymphocyte markers (immunoglobulin M and T-cell receptor for B and T lymphocytes, respectively), as analysed by semi-quantitative reverse transcription-polymerase chain reaction, was up-regulated in the head-kidney of melatonin-injected fish 1 and 3 days postinjection and decreased after 7 days. These data, together with our previous observations describing how photoperiod and in vitro melatonin treatment may affect seabream and sea bass immunology, confirm melatonin as a regulator of fish immunology. However, further studies are still needed to reveal the mechanisms underlying the direct or indirect interactions of melatonin with the fish immune system.
褪黑素是一种在脊椎动物的松果体和视网膜中产生的分子，在昼夜节律以及包括免疫反应在内的其他生理过程中发挥着重要作用。由于在这方面对鱼类了解甚少，我们评估了褪黑素在硬骨鱼金头鲷（Sparus aurata L.）主要先天性免疫活动中的体内作用以及免疫相关基因的表达。腹腔注射1或10毫克/千克体重的褪黑素会使循环血清褪黑素水平呈剂量 - 时间依赖性增加。在不同采样时间给予褪黑素后，几种先天性免疫反应，如过氧化物酶、吞噬作用、活性氧中间体和细胞介导的细胞毒性活性均显著增强。通过半定量逆转录 - 聚合酶链反应分析，免疫相关基因如白细胞介素 - 1β、主要组织相容性复合体、病毒相关反应（干扰素调节因子 - 1和Mx）以及淋巴细胞标志物（分别为B和T淋巴细胞的免疫球蛋白M和T细胞受体）的表达，在注射褪黑素的鱼注射后1天和3天，头肾中上调，7天后下降。这些数据，连同我们之前描述光周期和体外褪黑素处理如何影响金头鲷和海鲈免疫学的观察结果，证实褪黑素是鱼类免疫学的调节剂。然而，仍需要进一步研究来揭示褪黑素与鱼类免疫系统直接或间接相互作用的潜在机制。
